Quasicrystalline aluminum heat protection element and thermal spray

Abstract

A composite structure including a substrate and a heat protection element on the substrate, wherein the heat protection element includes a quasicrystalline aluminum alloy of one or a number of quasicrystalline phases which are either quasicrystalline phases in the strict sense, or approximating phases, wherein the quasicrystalline phases exhibit a thermal diffusivity, measured at ambient temperature, lower than 2.5.times.10.sup.-6 m.sup.2 /s, and a thermal diffusivity measured in the temperature range 650.degree.-750.degree. C. which does not exceed the thermal diffusivity measured at ambient temperature by more than a factor of 3, and wherein the quasicrystalline aluminum alloy comprises Al.sub.a Pd.sub.b Mn.sub.c X.sub.d Y.sub.e T.sub.f I.sub.g, wherein X represents at least one metalloid selected from the group consisting of B, C, Si, Ge, P, and S; Y represents at least one metal selected from the group consisting of Fe, Mn, V, Ni, Cr, Zr, Hf, Mo, W, Nb, Ti, Rh, Ru, Re, and Ta; T is at least one rare earth; I represents the unavoidable production impurities; and wherein a+b+c+d+e+f+g=100 atom %; 15.ltoreq.b.ltoreq.25; 6.ltoreq.c.ltoreq.16; 21.ltoreq.b+c+e.ltoreq.45; 0.ltoreq.f.ltoreq.4; 0.ltoreq.g.ltoreq.2; 0.ltoreq.d.ltoreq.5.